| Message ID | 1443608912-31667-14-git-send-email-chandan@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 09/30/2015 06:28 AM, Chandan Rajendra wrote: > The following issue was observed when running generic/095 test on > subpagesize-blocksize patchset. > > Assume that we are trying to write a dirty page that is mapping file offset > range [159744, 163839]. > > writepage_delalloc() > find_lock_delalloc_range(*start = 159744, *end = 0) > find_delalloc_range() > Returns range [X, Y] where (X > 163839) > lock_delalloc_pages() > One of the pages in range [X, Y] has dirty flag cleared; > Loop once more restricting the delalloc range to span only > PAGE_CACHE_SIZE bytes; > find_delalloc_range() > Returns range [356352, 360447]; > lock_delalloc_pages() > The page [356352, 360447] has dirty flag cleared; > Returns with *start = 159744 and *end = 0; > *start = *end + 1; > find_lock_delalloc_range(*start = 1, *end = 0) > Finds and returns delalloc range [1, 12288]; > cow_file_range() > Clears delalloc range [1, 12288] > Create ordered extent for range [1, 12288] > > The ordered extent thus created above breaks the rule that extents have to be > aligned to the filesystem's block size. > > In cases where lock_delalloc_pages() fails (either due to PG_dirty flag being > cleared or the page no longer being a member of the inode's page cache), this > patch sets and returns the delalloc range that was found by > find_delalloc_range(). > > Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Thanks, Josef -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 0ee486a..3912d1f 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -1731,6 +1731,8 @@ again: goto again; } else { found = 0; + *start = delalloc_start; + *end = delalloc_end; goto out_failed; } }
The following issue was observed when running generic/095 test on subpagesize-blocksize patchset. Assume that we are trying to write a dirty page that is mapping file offset range [159744, 163839]. writepage_delalloc() find_lock_delalloc_range(*start = 159744, *end = 0) find_delalloc_range() Returns range [X, Y] where (X > 163839) lock_delalloc_pages() One of the pages in range [X, Y] has dirty flag cleared; Loop once more restricting the delalloc range to span only PAGE_CACHE_SIZE bytes; find_delalloc_range() Returns range [356352, 360447]; lock_delalloc_pages() The page [356352, 360447] has dirty flag cleared; Returns with *start = 159744 and *end = 0; *start = *end + 1; find_lock_delalloc_range(*start = 1, *end = 0) Finds and returns delalloc range [1, 12288]; cow_file_range() Clears delalloc range [1, 12288] Create ordered extent for range [1, 12288] The ordered extent thus created above breaks the rule that extents have to be aligned to the filesystem's block size. In cases where lock_delalloc_pages() fails (either due to PG_dirty flag being cleared or the page no longer being a member of the inode's page cache), this patch sets and returns the delalloc range that was found by find_delalloc_range(). Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> --- fs/btrfs/extent_io.c | 2 ++ 1 file changed, 2 insertions(+)